1. Field of the Invention
The present invention relates to an electromagnetic induction non-contact charger for charging a vehicle such as an electric automobile, in a non-contact fashion, using an electromagnetic inductive system.
2. Description of the Related Art
In conventional vehicle chargers, there is an inductive charging system in which charging is completed by connecting a feeding coupler and a receiver (a receiving coupler) in a non-contact fashion using electromagnetic induction. When compared with a conductive charging system, the inductive charging system can provide advantages in that there is no concern about a contact failure and that the receiver installed on the vehicle can be miniaturized easily.
The inductive charger uses a commercial alternating current power source, for example, and comprises a power source device (a power supply device) which converts a commercial alternating current into a charging alternating current (at a predetermined frequency and a predetermined voltage) suitable for charging and a feeding coupler mounted on the distal end of a feeding cable extending from the power source device. The feeding coupler can be inserted into an coupler inserting port of the receiver installed on the electric automobile, and a power transmitting coil (a primary coil) is built in the inserting portion of the feeding coupler. On the other hand, a receiving coil (a secondary coil) and a conversion circuit for converting a received alternating current into a direct current for charging are built in the receiver provided on the electric automobile.
In charging the electric automobile, the feeding coupler is inserted into the coupler inserting port of the receiver installed on the electric automobile. On detecting the insertion of the feeding coupler, the power source device outputs a current (an alternating current) having a voltage value in accordance with a battery residual capacity obtained through communication with the electric automobile. when the current outputted from the power source device flows through the power transmitting coil built in the inserting portion of the feeding coupler, a voltage is induced in the receiving coil on the receiver under the action of electromagnetic induction for charging.
The charger is set up at a public facility (such as a parking lot) for public use as a charging stand (a stand-type charger) in which the power source device is arranged upright on the stand. In addition, for family use, a wall mounted type power source device is available which is hung on the exterior wall of a house using a mounting bracket. Both types of chargers are set up outside a building for use.
Power-system electric components including a circuit for converting a commercial alternating current into a charging alternating current, and control-system electronic components including a control circuit are built in the power source device, and in particular, the power-system electric components generate heat, which causes a problem.
Circuits are disposed in the form of a circuit board, for example, in a housing or outer casing of the power source device. The circuit board is mounted on a cooling fin plate, and a cooling blower (a fan unit) is provided for blowing air for cooling the cooling fin plate through heat exchange. An intake hole and an exhaust hole are formed in, for example, the bottom of the housing, and the blower device is so disposed that an airflow is generated which circulates within the housing between the intake hole and the exhaust hole. Conventionally, the blower is provided in the vicinity of the exhaust hole. This is because the airflow is prevented from being heated by heat generated by the blower.
In order to obtain a required cooling effect, the flow rate and flow velocity of an airflow need to be equal to or higher than a certain level and, in order to generate an airflow meeting the requirement, for example, a large-sized and high-powered blower is needed which can provide a strong blowing force because, in the construction in which the blower is disposed in the vicinity of the exhaust hole, the cooling efficiency remains low for the large blowing capacity. Additionally, it is considered that the heat exchange efficiency of a cooling fin plate depends more on the flow rate and flow velocity of an airflow than on the increase in temperature of the airflow due to heat generated by the blower when it is normally used and, for example, and this has caused a problem that a sufficient cooling efficiency cannot be provided in a case where a relatively small-sized blower is preferably used in an attempt to miniaturize, for example, the power source device.
Additionally, as a factor determining the flow rate and flow velocity of an airflow there is raised a flow path cross-sectional area along the full length of the flow path of an airflow, and a certain flow path cross-sectional area is required along the full length of the flow path of an airflow from where outside air is taken into the flow path to where the air so taken in is then let out of the flow path in order to increase the cooling efficiency. In addition, since hot air is let out of the exhaust hole, it has been considered that the discharged hot air may be taken into the intake hole and that the hot air so taken into deteriorates the cooling efficiency. In consideration of these situations, countermeasures have been demanded for improving the cooling efficiency of chargers. Note that since chargers are set outside the building as a charging stand or a wall mounted type charger, in many cases, waterproofing measures must also to be taken into consideration.
The present invention is made to solve the aforesaid problems, and a first object thereof is to provide a charger for a vehicle, which can sufficiently cool electric components built into a power source unit. A second object of the present invention is, in addition to the first object, to improve the waterproofing with a simple construction.
According to a first aspect of the present invention, there is provided a charger, for a vehicle, comprising a power source unit and a feeding coupler connected to said power source unit via cable and adapted to be coupled to a receiver of a vehicle, said power source unit comprising: an outer casing having a top, a bottom with an intake hole and an exhaust hole; a duct having a vertically extending passage disposed in said outer casing, said passage having an upper opening and a lower opening; and a cooling blower disposed in said outer casing above said duct so that said blower causes a flow of air in which air is taken in said casing from said intake hole, enters said passage of said duct via said upper opening, flows down in said passage, and flows out of said outer casing via said lower opening and said exhaust hole.
In this arrangement, when the blower is driven, air is forced into the passage from the opening in the upper portion of the duct, an airflow is generated by the outside air, which is taken into the outer casing from the intake hole in the lower portion of the outer casing, being sent upward, then descending along the passage in the duct, and finally leaving from the exhaust hole. The electric components (including a circuit board) disposed in the outer casing are cooled by this airflow. Since the blower is disposed on the upper portion of the duct and an air suction system is adopted in which the blower is located at an intermediate position along the length of the airflow path, an airflow having required flow rate and flow velocity can be generated within the passage in the duct with a relatively weak blowing force, and this can increase the cooling efficiency. In addition, since the blower is disposed on the upper portion of the duct and, hence, the blower is located at a relatively high position within the outer casing, should water penetrate into the interior of the outer casing, the blower is not submerged in the water penetrating into the outer casing.
Preferably, the duct comprises a cooling fin plate formed into a duct-like shape, and a circuit board having electric components mounted thereto is directly attached to the cooling fin plate.
In this arrangement, in addition to the operation set forth in the first aspect, the heat generated at the circuit board is heat exchanged via the cooling fin plate by the airflow passing the passage in the duct, whereby the circuit board is efficiently cooled. In addition, since the cooling fin plate also functions as a constituting component of the duct, the number of components used can be reduced, and this facilitate making compact the interior of the outer casing, whereby miniaturization of the power source device is made possible.
Preferably, the support board to which the duct is attached is made of metal.
In this arrangement, in addition to the above operation, since the support board to which the duct is attached is metallic and provides a high heat conductivity, the heat escapes from the duct to the support board, whereby the cooling effect on the electric components constituting the circuit board is increased.
Preferably, the top of the outer casing is inclined, and the blower is disposed in an inclined posture in accordance with the inclination of the top of the outer casing.
In this arrangement, even though the top of the outer casing is inclined, the height of the outer casing can relatively be low, whereby the miniaturization of the power source unit can be facilitated.
According to a second aspect of the present invention, there is provided a charger, for a vehicle, comprising a power source unit and a feeding coupler connected to said power source unit via a cable and adapted to be coupled to a receiver of a vehicle, said power source unit comprising: an outer casing having a top, a bottom with an intake hole and an exhaust hole; a duct having a vertically extending passage disposed in said outer casing, said passage having an upper opening and a lower opening; a cooling blower disposed in said outer casing above said duct so that said blower causes a flow of air in which air is taken into said casing from said intake hole, enters said passage of said duct via said upper opening, flows down in said passage, and flows out of said outer casing via said lower opening and said exhaust hole; and a support board to which said duct is attached being made of metal, said outer casing being assembled onto said support board.
In this arrangement, when the cooling blower is driven, an airflow is generated in which the outside air is taken into the outer casing from the intake hole in the lower portion of the outer casing and is then caused to descend along the passage in the duct and is finally let out from the exhaust hole in the lower portion of the outer casing. The electric components (including the circuit board) disposed inside the outer casing are cooled. Since the support board to which the duct is attached is made of metal and hence has a high heat conductivity, the heat escapes from the duct to the support board, whereby the cooling effect on the electric components can be improved. The number of components disposed within the outer casing can be reduced, the miniaturization of the power source device being facilitated.
Preferably, a reinforcing tubular structure is formed on the support board, the outer casing being fixed to the tubular structure by fastening members extending in assembling holes formed in the tubular structure, the interior of the tubular structure which communicates with the assembling holes functioning as a water drain passage.
In this arrangement, the outer casing is assembled to the support board via the assembling holes formed in the tubular structure using the fastening members. Even if water penetrates into the outer casing from a gap between the fastening member and the assembling hole, the water so penetrating flows downward through the drain passage within the interior of the tubular structure and is let out of the drain passage. Consequently, a risk that the electric components accommodated within the outer casing are submerged in water is eliminated. In addition, since reinforcement is implemented with the tubular structure, with the support board, it is possible to secure a high strength for the thickness of the support board.
Preferably, an electric circuit is disposed in the passage of the duct.
In this arrangement, since the electric circuit is disposed within the passage in the duct, not only can the electric circuit be cooled, but also the accommodating space within the outer casing can be saved on, whereby this construction can contribute to the miniaturization of the power source.
According to a third aspect of the present invention, there is provided a charger, for a vehicle, comprising a power source unit, a feeding coupler connected to said power source unit via a cable and adapted to be coupled to a receiver of a vehicle, and a stand supporting the power source unit; said power source unit comprising: an outer casing having a top, a bottom with an intake hole and an exhaust hole; a duct having a vertically extending passage disposed in said outer casing, said passage having an upper opening and a lower opening; a cooling blower disposed in said outer casing above said duct so that said blower causes a flow of air in which air is taken into said casing from said intake hole, enters said passage of said duct via said upper opening, flows down in said passage, and flows out of said outer casing via said lower opening and said exhaust hole; said stand comprising a tubular body having an internal space and outlet holes formed through said tubular body, said power source unit being fixed to said stand with said exhaust hole in communication with said internal space; and louvers formed separately from and attached to said tubular body so that said louvers substantially cover said outlet holes, as viewed in a direction perpendicular to an outer surface of said tubular body, and an extending length of said louver measured from said tubular body in said direction is longer than that of a louver which is formed by a drawing process.
In this arrangement, when the cooling blower is driven, an airflow is generated in which the outside air is taken into the outer casing from the intake hole in the lower portion of the outer casing and is then caused to descend along the passage in the duct and is finally let out from the exhaust hole in the lower portion of the outer casing. The electric components (including the circuit board) disposed inside the outer casing are cooled. The exhaust air let out from the exhaust hole into the interior of the stand is guided from the outlet holes to the louvers, where it is discharged to the outside. In this case, the louvers are made as the separate members for fixation, and when compared with one formed through a drawing process, the extending length over which the louver extends is made longer and the opening area of the louver can be secured wider, whereby the flow cross-sectional area along the full length of the airflow path can be secured widely, and the circulation of the air in the outer casing is improved, whereby a better waterproof effect can be obtained. In addition, since the louvers extend such that the exhaust hole is substantially concealed thereby when viewed from the front, rain or the like will tend not to enter the stand through the outlet holes, whereby the waterproof effect within the stand can be secured.
Preferably, a resin distribution box to which a power source wiring connected to the power source unit is connected is disposed in the stand below the outlet holes and wherein an air shielding member is provided for preventing hot air let out from the exhaust hole from flowing toward the distribution box.
In this arrangement, the hot air let out from the exhaust hole is guided toward the outlet holes in such a manner as to be prevented from flowing toward the resin distribution box by the air shielding member. Due to this, the resin distribution box disposed inside the stand is protected from the hot air.
According to a fourth aspect of the present invention, there is provided a charger, for a vehicle, comprising a power source unit and a feeding coupler connected to said power source unit via a cable and adapted to be coupled to a receiver of a vehicle, said power source unit being of a wall mounted type and comprising: an outer casing having a top, a bottom with an intake hole and an exhaust hole; a duct having a vertically extending passage disposed in said outer casing, said passage having an upper opening and a lower opening; a cooling blower disposed in said outer casing above said duct so that said blower causes a flow of air in which air is taken in said casing from said intake hole, enters said passage of said duct via said upper opening, flows down in said passage, and flows out of said outer casing via said lower opening and said exhaust hole; and a partition member disposed below said outer casing for separating a region including said exhaust hole from a region including said intake hole.
In this arrangement, when the cooling blower is driven, an airflow is generated in which the outside air which is taken into the outer casing from the intake hole in the lower portion of the outer casing, is then caused to descend along the passage in the duct and is finally let out from the exhaust hole in the lower portion of the outer casing. The electric components (including the circuit board) disposed inside the outer casing are cooled. The air entering the intake hole and the air let out of the exhaust hole are separated from each other by the partition member provided at the lower portion of the outer casing so as not to mix with each other. This eliminates a risk of the hot air let out of the exhaust hole being taken directly into the intake hole. This allows relatively low temperature air to be taken into the outer casing, whereby the cooling effect on the electric components provided inside the outer casing can be improved.